When people ask whether modern synthetics are damaging their health and endangering future generations, Topic A is nearly always bisphenol A (BPA), a synthetic estrogen, an integral component of polycarbonate plastics and epoxy resins and one of the highest volume industrial chemicals in existence.
Now a ground-breaking study released in the journal of Human Reproduction offers what its authors call "the first evidence that exposure to BPA in the workplace could have an adverse effect on male sexual dysfunction."
The scientific team, underwritten by Kaiser Permanente's Division of Research in Oakland, CA., spent five years studying 634 Chinese factory workers whose bodies had been severely contaminated with BPA.
Animal studies link BPA to an extraordinary array of subtle but serious chronic health problems, including impairment of the ability to think and behave normally, reproductive and cardiovascular system damage, cancer, diabetes, asthma and obesity. Evidence of BPA's impact on human health has been more elusive, which is why the Kaiser Permanente study is making headlines around the globe.
After a year of being bombarded with BPA, the Chinese workers reported disturbing sexual problems: four times as much erectile dysfunction and seven times as many ejaculation difficulties as a control group, the Kaiser team found.
Most people don't experience BPA exposure nearly as intense as the factory workers. But nearly all Americans test positive for low-level BPA contamination, as evidenced by body burden testing by the U.S. Centers for Disease Control and Prevention, the Environmental Working Group and other academic and non-profit organizations.
As Kaiser research team leader De-Kun Li, MD, Ph.D., put it, the China workers study "raises the question: Is there a safe level for BPA exposure, and what is that level?"
Many scientists specializing in hormonal and reproductive systems say there's no such thing as a "safe" dose of BPA, a powerful endocrine-disrupting chemical. Earlier this week, the American Medical Association Board of Delegates resolved to work with the federal government to minimize the public's exposure to BPA and other endocrine-disrupting chemicals. The measure was proposed by the Endocrine Society, which, with 14,000 hormone researchers and medical specialists in more than 100 countries, recently warned that "even infinitesimally low levels of exposure [to endocrine-disrupting chemicals] -- indeed, any level of exposure at all -- may cause endocrine or reproductive abnormalities, particularly if exposure occurs during a critical developmental window. Surprisingly, low doses may even exert more potent effects than higher doses."
"The AMA represents a very important constituency of physicians who have a lot of credibility and clout," says Andrea Gore, Ph.D., a University of Texas-Austin researcher who co-authored the Endocrine Society statement. "If members of the AMA can now get behind the statement and actually affect regulations, then I think we can consider it a victory."
Most of the BPA in Americans' bodies is believed to come as a result of leaching from BPA-based epoxy food can linings and polycarbonate baby and drink bottles, sippy cups and other food containers. Under pressure from EWG and other scientific and environmental health groups, the federal Food and Drug Administration is weighing proposals to ban the chemical in food packaging.
Because of FDA inaction, last October EWG president Ken Cook wrote major infant formula and canned food producers urging them to take voluntary measures to remove BPA from their can linings.
Laboratory tests commissioned by EWG in 2007 found BPA in 20 out of 28 brands of canned food and drink, including B&M, Bush's Best, Campbell's Condensed (soup), Campbell's Chunky, Campbell's SpaghettiOs, Chef Boyardee, Chicken of the Sea, Coca-Cola, Del Monte, Dole, Ensure, Green Giant, Kroger store brand, Libby's, Nestle Carnation, Pepsi-Cola, Progresso, S&W, Slim-Fast, Swanson and Wolfgang Puck.
An EWG survey found that all four leading makers of liquid infant formula sold in North America used BPA to line their cans. These included Nestle (Good Start), Ross-Abbot (Similac and Isomil), MeadJohnson (Enfamil), and PBM (maker of store-brand formulas sold at Target, Kroger and dozens of other retailers).
Last week, Consumers Union, an advocacy organization, reported that its laboratory tests had found BPA in canned food packaged under the brand names Campbell's Condensed, Progresso, Del Monte and Nestle.
The FDA's plans are, as yet, unclear. But other top administration scientists and regulators are zeroing in on BPA. Lisa Jackson, administrator of the U.S. Environmental Protection Agency, has identified BPA as a priority for regulatory action. And Linda Birnbaum, director of the National Institute for Environmental Health Sciences, has recently committed $30 million in federal stimulus funds to research the many unanswered questions about BPA.
We know this much: With every day that passes, the cases against BPA hardens, like the plastics it makes.
Check out Environmental Working Group's guide to low-BPA infant formula.